261A
As metioned by someone above, ditch the BT Router.
ICS should be avoided like the plague and although I am sure there are many who have got it to work, there are many good reasons why it should not be used (Security, problems with AV software, problems with Windows XP SP2 firewall to name but a few... oh and needing to have the first PC on if you are using a USB cionnection to your router as well.)
I have several computers sharing a netgear router here, both by cable and wireless (cabled PCs via a switch as well). It is fairly easy to setup if you start off with the basics and then build up a secure setup. The secret is to take it a step at a time.....
Go to a certain large PC Emporium where you can currently buy a Netgear Wireless ADSL router/firewall for around £70 on special offer. (DG834GT or similar)
Get a network cable for the desktop.
When you get home again, first log on to your router and get your login. (BT don't use a password for access) The login is usually
[email protected] (or a few variations), where xxx is a number.
Plug desktop into new router and login. Setup BT login in router setup and then plug in ADSL line.
Before going any further, get this to connect to the internet first.
Then get wirelss working for laptop. Alternatively use another cable.
Sorry, short and sweet answer, but it is rather late...
If you want ot go down this road, I'm sure there are some of us who will help hold your hand....
Regards,
Shuttlebus
P.S. Since I can't determine if your PCs have network ports, I won't gaurantee you end up spending nore than the cost of the router....